Most refrigeration breakdowns give warning before they happen. A condenser clogged with kitchen grease and dust makes the compressor run hot and long; a torn door gasket lets in warm, humid air that causes icing; a blocked drain floods the cabinet floor. Preventive maintenance finds and fixes these problems on a schedule. Typical tasks include cleaning condenser coils, checking and cleaning gaskets, clearing drain lines, checking fan motors, verifying the controller and thermometer, inspecting electrical connections and checking temperatures and running times.
Some tasks belong to the operator, such as wiping gaskets, keeping vents clear and cleaning accessible condenser grilles; others need a trained technician. How often depends on the environment. A unit in a dusty roadside shop or a greasy tandoor kitchen needs condenser cleaning far more often than one in a clean, air-conditioned space.
A QSR chain in Delhi might schedule monthly in-house condenser cleaning and gasket checks at every outlet, plus quarterly technician visits under an AMC, with each visit logged against the unit's serial number.